London's Iranian embassy siege came at a time of great turmoil within Iran itself. The hostage takers- Iranian Arabs demanding autonomy for their southern region of Khuzestan - were among a number of groups trying to take advantage of the chaos following the 1979 Islamic Revolution to further their own cause.

The Revolution had temporarily united disparate groups, including Islamist, leftist and communist groups in their desire to overthrow the autocratic Shah.

But by early 1980 it was becoming clear that pro Islamic forces were winning an internal power struggle, with clerics surrounding the revolution's leader, Ayatollah Khomeini, increasingly in control.

The hostage-takers were protesting against oppression by Khomeini

In a tape recording which survived the London siege, one of the gunmen said people had joined the revolution because it hoped that the new leaders "would give them the freedom which had been stolen by the Shah and his father." But he concluded that once they were in power "the new leaders forgot all their promises to the people."

The Iranian Government appeared satisfied with the outcome of the siege, thanking the British police for " the perservering action of your police force during the unjust hostage-taking event at the Embassy."

Mutual compensation

Nevertheless, it was some years before the two countries reached agreement on a mutual compensation agreement under which London paid Iran for damage done to the Princes Gate Embassy during the siege and Iran compensated Britain for damage caused to its Tehran Embassy during the Islamic Revolution.

Fire gutted the embassy: It was left empty for years

Iranian diplomats were forced to work elsewhere in London while the compensation issue was being settled and repair work was carried out. The Princes Gate embassy was not officially re-inaugurated until December 1993.

The group which claimed responsibility for the siege- the Arab Popular Movement in Arabistan- gave a number of press conferences in the following months, referring to what it described as "the racist rule of Khomeini".

It threatened further international action as part of its campaign to gain self- rule for Khuzestan.

Iran-Iraq war

But its links with Baghdad served to undermine its argument that it was a purely Iranian opposition group; there were allegations that it was backed by Iran's regional rival, Iraq.

Awn Ali Mohammed: the leader of the Iranian gunmen

By late 1980, Baghdad and Tehran had embarked on a bloody war which was to preoccupy them for the next eight years.

Calls for autonomy for Khuzestan came to nothing as both countries concentrated on the war effort and the increasingly Islamic administration in Tehran moved to suppress internal dissent. The hostage takers of Princes Gate-and their cause- were largely forgotten.